https://www.khanacademy.org/science/cambridge-o-level-biology-cie/x2a084a90105205d2:disease-and-immunity/x2a084a90105205d2:active-immunity-and-vaccination/v/vaccination-the-world-of-microorganisms-grade-8-science-khan-academy-1080p 2026-04-20T05:10:45.627247989Z Vaccination-The World of Microorganisms Vaccination The World of Microorganisms Khan Academy Pakistan video https://cdn.kastatic.org/googleusercontent/ZCdwTudJg6e6n-P2gsaUborP4izvMsGo71pvEVlX9dNYWcLXcP7VHkWpn2grt4TUP1KoJLQP9NswyHBuBLSFTBw Vaccination-The World of Microorganisms Vaccination The World of Microorganisms https://cdn.kastatic.org/ka-youtube-converted/QLwFOHQ1J4k.mp4/QLwFOHQ1J4k.mp4 581 Infectious diseases https://www.khanacademy.org/college-careers-more/bjc/x4c51c62a:2020-challenge/x4c51c62a:2020-challenge-finalists/v/infection-impossible 2021-02-05T04:26:55Z Infection: Impossible By Weber Lin. Country: USA. Finalist: 2020 Breakthrough Junior Challenge. video https://cdn.kastatic.org/googleusercontent/ZCdwTudJg6e6n-P2gsaUborP4izvMsGo71pvEVlX9dNYWcLXcP7VHkWpn2grt4TUP1KoJLQP9NswyHBuBLSFTBw Infection: Impossible By Weber Lin. Country: USA. Finalist: 2020 Breakthrough Junior Challenge. https://cdn.kastatic.org/ka-youtube-converted/t7lojYX9LTA.mp4/t7lojYX9LTA.mp4 180 Infectious diseases